1. Field of the Invention
This invention pertains to technologies for controlling machines and processes in which fabrics are washed, laundered, dyed, or otherwise treated in a liquid bath. This invention especially relates to controlling, inducing, or abating the transfer of coloration to or from fabrics in such machines or processes.
2. Background of the Invention
Present day clothes washing technology fails to adequately address a problem of color bleeding from one clothing article to another. This is true of residential clothes washing machines, as well as commercial and industrial clothes washing machines. In this disclosure, we will refer to all machines and processes which are intended for washing fabric-based articles, whether they be clothes, rugs, bedding, linens, etc., collectively as “washing machines”, or as a “washing machine” in the singular. We will also use the term “article” to collectively refer to fabric-based items such as clothing, bedding, rugs, linens, etc. Further, the liquid solution and/or suspension in which the articles are washed will be referred to as a “bath liquid” in this disclosure. Groups of articles which are washed or otherwise processed together will be referred to as a “load” or “wash load”.
In one scenario, a newly purchased and previously unwashed article is introduced into a washing machine with other articles in a load. Depending on the color content and fabric composition of the unwashed article, the coloring substance (e.g. dye, pigment, etc.) may be released during the wash, and may settle in one or more of the other articles in the wash with it. This is called “color bleed”. It occurs with large color differences, such as placing a new red-colored item in a wash with light-colored items. In some instances, bath temperature or detergent may intensify the color bleed problem.
Several attempts have been made to attempt to avoid this problem. One attempt uses labeling of the articles, with warnings, icons, and symbols, that stipulate to wash a new item individually for a first wash, to wash like colors together, and to observe certain detergent and bath temperature instructions (e.g. wash cold only, no bleach, etc.). However, these labels are often not followed, usually by mistake by including a new item inadvertently in a wash group, by forgetting to read the label, or other user error.
Another attempt that has been made is to pre-wash articles before they are sold through retail stores, or even pre-washing fabrics before they are cut into panels and pieces for assembly into articles. However, this adds to the cost of the articles, which can be an economic disadvantage to the retail sales of the item. For some fabrics, pre-washing may increased the difficulty of handling the fabric during processing steps such as cutting, stitching, sewing, hemming, etc.
A decidedly higher-technology approach has been attempted by some makers of washing supplies in the form of a chemically-treated, disposable sheet which is introduced into the wash bath. The chemicals disposed on the sheet are of a nature that they bind to or absorb many types of coloring substances which are free floating in the bath liquid. While this approach may partially abate color bleeding, it remains incomplete in its effect, as each sheet can only remove a finite amount of coloring substance from the bath, and each sheet can only remove coloring substance with which it comes in contact. This still leaves many scenarios in which coloring substance may settle into articles, causing some amount of color bleed. Further, this approach can be expensive, and is prone to error by the user (e.g. forgetting to drop a sheet in each wash load).
In order to completely avoid color bleeding in common washing machines, operators are required to fully and correctly (a) sort articles by compatibility factors such as color; (b) follow initial or first-wash instructions posted on tags; (c) select appropriate wash settings; and (d) use appropriate wash additives (e.g. detergent, softener, etc.). This has proven for many years to be an onerous set of user requirements over the years, and a solution has eluded industry.
As a result, many articles are ruined every year. This results in economic loss to consumers to replace the damaged articles. And, it promotes brand disloyalty for clothing manufacturers because consumers often perceive color bleeding as a quality problem associated with a particular brand.
Further, many systems, such as industrial fabric dying systems, are employed to intentionally cause the transfer of dye to fabric items. Due to variations in fabric fibers, fabric content, water chemistry, and dye consistency, these processes are notoriously difficult to control. For example, using a batch or sample of a fabric to be dyed, and a sample quantity of dye, a set of parameters may be developed to establish a routine for dying larger quantities of fabric to achieve a certain color and shade. However, due to variations in the fabric, such as natural fibers being incorporated from different sources or geographic regions, each load of fabric to be dyed may take the dye differently from the pilot batch. Similarly, dying substances may also vary in large quantities, due to different plant and animal sources employed to render the dye, and due to changes in the chemistry of the water used in the bath (e.g. more or less minerals may change the transfer characteristics of the dying process).
As a result, commercial dying processes are not as accurate or efficient as desired, and often fabrics of undesirable color, shade or hue are yielded. These substandard fabrics are often scrapped or allocated to lower cost products, such as shredding the fabric for use in pillow fill, or using the fabrics for lower quality garments.